Hydraulic log grab attachment



Aug. 19, 1969 J. P. THOMAS HYDRAULIC LOG GRAB ATTACHMENT 2 Sheets-Sheet l Filed Oct. 31, 1967 0 2 a /////,//////.//////////7AVV 3 5 l l I 4 2 1 M o f 2 m 3 Y 2% 2 FIG. 3.

JOHN P. THOMAS INVENTOR.

A TTORNEV F IG. 2.

Aug. 19, 1969 J P. THOMAS 3,462,185

HYDRAULIC LOG GRAB ATTACHMENT Filed Oct. 31, 1967 2 Sheets-Sheet 2 FIG. 4.

JOHN-R moms I INVENTOR.

A T TORNEY United States Patent v 3,462,185 HYDRAULIC LOG GRAB ATTACHMENT John P. Thomas, P.0. Box 9496,

Fort Worth, Tex. 76107 Filed Oct. 31, 1967, Ser. No. 679,377 Int. Cl. B66c 1/10, 3/00; B25b US. Cl. 294-118 1 Claim ABSTRACT OF THE DISCLOSURE A hydraulic log grab for mounting on a prime mover such as a tractor and wherein the weight of the log increases the set pressure of the tongs. 'l he tongs are rotatably mounted on the end of at least one rearwardly extending arm or boom which is pivotally connected with the prime mover and operated in a vertical plane. In addition to a tong linkage whereby the weight of the log increases the set pressure, there is a hydraulic cylinder across the tong linkage for initially setting the tong points and for releasing the log.

This invention relates to log grabs mounted on prime movers and has reference to an improved log engaging tong construction.

Heretofore it has been the practice to use hydraulically operated clams which encircled one or more logs at a time, but obviously such clams did not firmly engage the logs to be lifted and hauled. Also, tongs capable of dragging logs were used, but did not include the present hydraulic cylinder across the tong linkage for init1ally setting the tong points and subsequently releasing the logs. Instead, constant hydraulic pressure was applied throughout the log moving operation.

The primary object of the present invention is to provide a log grab mounted on a prime mover and wherein increased pressure is applied to the points of the tongs by reason of the weight of the log suspended thereby.

Another object is to provide a tong linkage including a hydraulic cylinder across opposite pivot points of the tong linkage for initially setting the tong points and subsequently releasing the log being hauled, even when the prime mover is moving.

Another object is to provide a log grab as referred to which may be in the form of an attachment for prime movers.

Generally, the invention contemplates an economical and efficient log grab which is time saving in its operation.

These and other objects of the invention will become apparent from the following description and the accompanying drawings, in which:

FIGURE 1A is an elevational view of a tong assembly according to the invention.

FIGURE 1B is a side elevational view of the tong assembly supporting arm. FIGURES 1A and 1B are at right angles with respect to each other.

FIGURE 2 is an enlarged broken elevational and sectional view of the tong linkage of the preferred form of the invention mounted on the extending end of the supporting boom or arm.

FIGURE 3 is a view similar to FIGURE 2 but is taken at a right angle with reference thereto.

FIGURE 4 is a top plan view showing two positions of a tractor having two arms, a pair of tongs on each, first engaging and then initially towing bucked logs, and

FIGURE 5 is a side elevational view showing the logs being towed.

In the drawings the numeral generally designates a log grab for attachment to the back of a tractor T. The grab 10 shown includes a vertical mounting plate 11 and an upwardly and rearwardly disposed protector plate 12,

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the lower edges of which are connected by a narrow horizontal bottom plate 13. There are rearwardly extending sides 14 on the ends of the mounting plate 11 and there is a cross member 15 between the rear edges of the sides. The protector plate 12 is braced by brackets 16 connected between its ends and the sides 14. An arm 17, also herein referred to as a boom, is pivotally mounted at one end between the upper portions of the sides 14 by means of a transverse pin '18. The arm 17 is raised and lowered by a hydraulic cylinder 19, the closed end of which is pivotally mounted by a pin 20 on a gusset 21 which is mounted, as by welding, on the inner surfaces of the mounting plate 11, the protector plate 12 and the bottom plate 13. The piston rod 22 of the cylinder 19 is connected at 23 with 9. depending shoulder 24 on the arm 17 relatively near the pivoted end thereof and which arrangement locates the upper end of the cylinder betwen the cross member 15 and the upper portion of the protector plate 12.

The outer end 25 of the arm 17 extends upwardly at an angle where it rotatbaly receives a crank shaft 26 for rotation in a vertical plane. As shown in FIGURE 2, the crank shaft 26 is received in a bearing 27 and the upper end of the shaft has a shoulder 28 which turns on the upper surface of the arm extension 25. Similarly, there is a removable collar 29 around the crank shaft 26 just below the arm extension 25 to prevent vertical displace ment of the shaft. On the upper end of the shaft 26 there is a crank 30 having an upwardly extending wrist pin 31 to which a tie rod 32 is connected. In the form of the invention shown the tie rod 32 is connected with a lever mounted on the arm 17 near its inner end. To those versed in the art it will be obvious that other remote control means may be employed for selectively rotating the shaft 26, for example, a flexible cable assembly, not shown.

On the lower end of the shaft 26 there is a pivotally connected supporting rod '34 which pivotally supports a tong assembly 35. The upper end of the rod 34 is connected to the shaft 26 by a pivot pin 36 and the lower end of the rod supports the long assembly by another pin 37. It is to be noted that the two pins 36 and 37 are at a right angle to each other so as to provide a universal action.

The lower end of the supporting rod 34 is fiat on opposite sides to accommodate a pair of links 38 on the one side and a pair of linkage plates 39 on the other. In the appended claim the plates 39 are also referred to as links, the same as the first described links 38. As best shown in FIGURE 2, there is a double acting hydraulic cylinder 40 between the plates 39, the closed end of which cylinder is pivotally mounted, at 41, near the outer edges of the plates, whereas the extending end of the piston rod 42 is pivotally mounted between the links 38, at 43, near the lower ends thereof. Flexible hydraulic lines 44 are connected with the ends of the cylinder 40 in the usual manner.

Scissors type tong arms 45 are pivotally connected with each other, at 46, near their upper ends and which upper ends are connected, at 47, to the lower ends of the links 38 and the link plates 39. The points 48 of the tong arms 45 are pointed upwardly and inwardlly when the tong arms are closed, and when the arms are completely open the points are never pointed lower than horizontal.

Referring now to FIGURES 4 and 5, there are two log grabs 10 mounted on the back of the tractor T, and as shown in position A of FIGURE 4 the tong assemblies 35 are positioned over the bucked ends of logs L of a felled tree. The cylinders 40 are then actuated in a direction to cause the points 48 of the respective pairs of tong arms 45 to engage opposite sides of the logs L, after which the arms 17 are raised by the first described cylinders 19. Initially, when the tractor T moves forward, the logs L take angular positions as shown in position B in FIGURE 4, and after which they drag behind the tractor T as shown in FIG- URE'5;'Beca'use of the described extending angle '25 of each arm 17. the angle of the shaft 26 therethrough and the pivotal connection of the supporting rod 34, the supported ends of the logs L are lifted when the tractor turns." Operation of the cylinder 40 in a direction to expand the tong arm points 48 will release the logs, even while the tractor is moving. By reason of the described scissors type tong assembly and arrangement of points 48 on the tong arms 45, the Weight of a lifted log increases the grip of the tongs.

The invention is not limited to the constructon herein shown and described, but may be made in various Ways within the scope of the appended claim.

What is claimed is:

l. A log grab for mounting on a prime mover, said log grab being comprised of an arm pivotally mounted at one end to said prime mover for vertical movement, a depending scissors type tong assembly beneath the extending end of said arm, means rotatably and hingedly supporting said tong assembly, means raising and lowering said arm, means selectively rotating said tong assembly, means selectively opening and closing said tong assembly,

and wherein the extending end of said arm is turned up- Wa'r'dly at an angle with" reference to itsinte r me'diaf e length, a rotatable shaft through said extending end perpendicular to the upper and lower edges thereof, a supporting rod above said tong links pivotally connecting the upper ends of said tong arms with saidrod, a hydraulic cylinder connected across said links, and wherein said means rotatably and hingedly supporting said tong assembly include a pivot connecting the upper end of said supporting rod with the lower end of said shaft.

References Cited UNITED STATES PATENTS 2,050,548 8/1936 Uhren et a1 294-118 2,991,891 7/1961 Wills 214-147 3,069,034 12/1962 Thornton 214-147 3,079,020 2/1963 Gustine 214147 ANDRES H. NIELSEN, Primary Examiner US. Cl. X.R. 214447 

